Final answer:
The anterior cardiac veins drain the right ventricle and empty directly into the right atrium, unlike the small cardiac veins at the back of the heart that lead to the great cardiac vein before entering the atrium.
Step-by-step explanation:
The anterior cardiac veins are vessels that drain the anterior surface of the right ventricle and bypass the coronary sinus to drain directly into the right atrium. In contrast, at the back of the heart, the small cardiac veins drain into larger veins and ultimately into the great cardiac vein, then into the right atrium. Not all blood from the ductus venosus passes directly into the left atrium through the foramen ovale, as a portion also goes from the right atrium into the right ventricle.
The right atrium is the chamber that receives systemic blood from the superior and inferior venae cavae and the coronary sinus. The superior vena cava drains regions above the diaphragm while the inferior vena cava drains regions below, with both emptying into the right atrium. Blood from the myocardium of the heart is mostly drained by the coronary sinus, which also empties into the right atrium.